1. Field of the Invention
The present invention generally relates to an image forming apparatus, such as a printer, a copy machine, a facsimile which can form an image using an electro photographic method, and more particularly to a replacement assembly for the image forming apparatus, which is attachable to a main body of the image forming apparatus and is able to determine the quantity of toner in a toner container, such as a toner cartridge, and an integrated circuit chip therefor.
2. Description of the Related Art
Conventionally, a toner cartridge or a toner bottle for the image forming apparatus, such as a printer which forms images using an electro photographic method, is supplied as one of the replacement parts, which enables a user to replace the toner cartridge or the toner bottle.
It is desirable to have a measuring method to know the amount of unused toner in the toner cartridge so that the cartridge can be replaced at a proper time before the toner cartridge becomes empty so as not to damage the quality of the printed image.
To meet this demand, conventionally, a detector for detecting the amount of the unused toner, such as a toner sensor, is used. For example, the detector which has a light source and a photo detector inside the toner bottle is in practical use and a detection method in which the amount of unused toner in the toner bottle is detected using a sound wave is also proposed.
Further, another detection method in which a density sensor placed at the bottom of a toner tank in a development unit to which the toner is supplied from the toner cartridge is also proposed. In this method, an empty toner bottle is detected when an output of the density sensor becomes greater than a predetermined threshold value, because the less the toner remaining in the toner cartridge, the lower becomes the toner density at the bottom of the toner tank, and as a result of it, the output value from the inversely proportional density sensor is increased.
However, the former method in which a detector for detecting the amount of the unused toner is used results in a complicated construction of the main body which holds the toner bottle or a complicated construction of the toner bottle itself. This raises the cost of the image forming apparatus and the replacement assembly. Further, if the detector becomes inoperable, the amount of the unused toner can not be calculated accurately.
The latter method in which the density sensor is placed at the bottom of a toner tank in a development unit, poses a problem of a mis-detection. A fluctuation of the amount of used toner depending on a printing speed or contents of images, and furthermore a delay of feeding the toner cause a fluctuation of the toner density. As a result, the toner density is mis-detected and then this mis-detection causes a fluctuation of the sensor output because the density sensor placed at the bottom of the toner tank only detects a local density.
FIG. 13 shows output samples from the sensor under these conditions in the prior art. FIG. 13 shows a fluctuation of sampled values of the sensor output for each color (Y: yellow, M: Magenta, C: Cyan and K: Black) in every page when color images are printed. A horizontal axis shows sampling points and a vertical axis shows the sensor output voltage V. The lower the density becomes, the greater the output voltage becomes. FIG. 13 shows the fluctuations of the sensor output causing the fluctuations of the toner density under regular conditions. For example, M becomes higher than 3 V at a sampling point around 73. This is caused by a condition where little unused toner remains in the toner tank and the toner density is gradually decreasing. Therefore, if the threshold value of toner is set to 3 V, then the end of the toner will be indicated in spite of toner remaining in the toner tank.
It is a general object of the present invention to provide an image forming apparatus in which the above disadvantages are eliminated using a means for calculating the amount of the unused toner in a toner bottle. In the image forming apparatus which has a replacement assembly for the image forming apparatus, such as a toner cartridge, which is attachable to a main body of the image forming apparatus, an exact amount of the unused toner in a toner cartridges is monitored without using a conventional toner end sensor in the toner cartridge.
To meet the above mentioned demand, according to the present invention, each period for feeding toner into a development unit in the main body of the image forming apparatus from the toner container is accumulated. Then, the amount of the unused toner remaining in the toner bottle is estimated based on the total accumulated period. Further, it is another object of the present invention to provide an image forming apparatus which can adapt to a printing speed even if it is changed. Therefore, according to the present invention, it is possible to estimate the exact amount of the unused toner remaining in the toner bottle even if the feeding speed of the toner is changed according to the printing speed. Further, it is another object of the present invention to provide an image forming apparatus which can efficiently manage information pertaining to the amount of the unused toner for each toner bottle among a plurality of the toner bottles, a replacement assembly for such an image forming apparatus and an integrated circuit chip therefor.
Further, it is another object of the present invention to provide an image forming apparatus which can exactly detect an end of the toner, that is, when all the toner has been used, without causing a mis-detection even if a conventional toner density sensor placed at the bottom of a toner tank in a development unit is used.
To meet the above mentioned demand, according to the present invention, the end of the toner is detected using the conventional toner density sensor placed at the bottom of a toner tank after the above mentioned total accumulated period for feeding the toner is increased over a predetermined threshold value.
Further, it is another object of the present invention to provide an image forming apparatus which can adapt to a changing printing speed. Therefore, according to the present invention, it is possible to estimate the exact amount of the unused toner remaining in the toner bottle even if the feeding speed of the toner is changed according to the printing speed. Further, it is another object of the present invention to provide an image forming apparatus which can efficiently manage the information pertaining to the amount of the unused toner for each toner bottle among a plurality of toner bottles, a replacement assembly for such an image forming apparatus and an integrated circuit chip therefor.
The above objects of the present invention are achieved by an electro photographic image forming apparatus comprising:
a replacement assembly having a toner container attachable to the image forming apparatus;
a feeding unit to feed toner from the toner container to a development unit; and
a read/write non-volatile memory;
wherein, the image forming apparatus comprising:
an estimation unit which generates information in such way that first, the estimation unit obtains an amount of a toner feed period for the feeding unit during forming images, next, accumulates the amount of a toner feed period into an accumulated sum of the amount of a toner feed periods, then, generates the information on the amount of toner in the replacement assembly and stores the information in the read/write non-volatile memory.
According to the invention, the exact information on the replacement assembly can be managed without a complicated construction of the main body or the toner bottle itself and without raising the cost. As a result, this enables proper management of the replacement assemblies according to the present invention.
The above objects of the present invention are achieved by an electro photographic image forming apparatus comprising:
a replacement assembly having a toner container attachable to the image forming apparatus;
a feeding unit to feed toner from the toner container to a development unit;
a toner detection unit which detects a density of the toner in the development unit and detects that all the toner is used in that the toner container is completely empty; and
a read/write non-volatile memory;
wherein, the image forming apparatus comprising:
an estimation unit which generates information in such way that first, the estimation unit obtains an amount of the toner feed periods for the feeding unit during forming images, next, accumulates the amount of the toner feed period into an accumulated sum of the amount of a toner feed periods, then stores the accumulated sum in the read/write non-volatile memory and causes the toner detection unit to start detecting the amount of the toner contained in the toner container after the accumulated sum exceeds a predetermined threshold value.
According to the present invention, an end of the toner is calculated exactly without causing a mis-detection even if a conventional toner density sensor placed at the bottom of a toner tank in a development unit is used. As a result, this enables the management of the replacement assemblies according to the present invention.
The above objects of the present invention are achieved by the image forming apparatus, wherein the image forming apparatus is able to operate under a plurality of image forming conditions,
when a linear velocity for feeding the toner is changed according to the image forming condition, the estimation unit compensates for the amount of the toner used during a feed period during forming images according to the changed linear velocity.
The above objects of the present invention are also achieved by the image forming apparatus, wherein the estimation unit separately stores each accumulated sum for each linear velocity in the read/write non-volatile memory.
According to the present invention, an exact estimate of the amount of the toner is provided when the image forming apparatus is able to operate under a plurality of image forming conditions.
The above objects of the present invention are achieved by the image forming apparatus, wherein the estimation unit calculates a sole accumulated sum from a plurality of the compensated amounts of toner used during the feed period for a plurality of linear velocities.
According to the present invention, it is possible to reduce a memory area to store information on the accumulated sum.
The above objects of the present invention are achieved by the image forming apparatus, wherein the read/write non-volatile memory is placed in the replacement assembly.
According to the invention, it is possible to store information on the amount of the toner in each toner bottle and to properly manage the data for each bottle.
The above objects of the present invention are achieved by an IC chip attachable to an electro photographic image forming apparatus, the IC chip having a read/write non-volatile memory which is connected to a CPU in the electro photographic image forming apparatus when the IC chip is attached to the electro photographic image forming apparatus and is controlled by the CPU, wherein
an accumulated sum of an amount of toner feed periods during which toner is supplied from a toner container to a development unit in the image forming apparatus, is stored in the read/write non-volatile memory,
the accumulated sum is read from the read/write non-volatile memory when the IC chip is attached to the image forming apparatus,
the accumulated sum read from the read/write non-volatile memory is transferred to a main body of the image forming apparatus,
a new accumulated sum of the amount of the toner feed periods is calculated when the toner is supplied from a toner container to a development unit in the image forming apparatus, and
the new accumulated sum is rewritten over the accumulated sum which is already stored in the read/write non-volatile memory.
The above objects of the present invention are also achieved by the IC chip as claimed in claim 7, wherein the IC chip separately stores each accumulated sum for each linear velocity in the read/write non-volatile memory.
According to the present invention, it is possible to store information pertaining to the amount of the toner in the IC chip as a removable media. As a result, it is possible to properly manage information on the amount of the toner for each user of the IC chip as the removable media.
The above objects of the present invention are achieved by a replacement assembly having a toner container attachable to the image forming apparatus comprising the IC chip.
According to the invention, it is possible to store information on the amount of the toner in the toner container and to properly manage the data for each toner container.